<?hh 

class DateTimeExt1 extends DateTime {
}

class DateTimeExt2 extends DateTime{
	public $foo = "Hello";
	private $bar = 99;
}

class DateTimeExt3 extends DateTimeExt2 {
}
<<__EntryPoint>>
function main_entry(): void {

  echo "Simple test for DateTime compare object handler\n";

  //Set the default time zone 
  date_default_timezone_set("Europe/London");

  $obj1 = new DateTime("2009-02-12 12:47:41 GMT");
  $obj2 = new DateTimeExt1("2009-02-12 12:47:41 GMT");
  $obj3 = new DateTimeExt2("2009-02-12 12:47:41 GMT");
  $obj4 = new DateTimeExt3("2009-02-12 12:47:41 GMT");

  echo "\n-- All the following tests should compare equal --\n";
  var_dump($obj1 == $obj1);
  var_dump($obj1 == $obj2);
  var_dump($obj1 == $obj3);
  var_dump($obj1 == $obj4);
  var_dump($obj2 == $obj3);
  var_dump($obj2 == $obj4);
  var_dump($obj3 == $obj4);

  date_modify($obj1, "+1 day"); 
  echo "\n-- The following test should still compare equal --\n";
  var_dump($obj1 == $obj1);
  echo "\n-- All the following tests should now compare NOT equal --\n";
  var_dump($obj1 == $obj2);
  var_dump($obj1 == $obj3);
  var_dump($obj1 == $obj4);

  echo "\n-- All the following tests should again compare equal --\n";
  date_modify($obj2, "+1 day");
  date_modify($obj3, "+1 day");
  date_modify($obj4, "+1 day");   
  var_dump($obj1 == $obj2);
  var_dump($obj1 == $obj3);
  var_dump($obj1 == $obj4);
  echo "===DONE===\n";
}
